Front differential leak

TYRANOMIKE

MEMBER
2004 BMW X5
V8
AWD
AUTOMATIC
75,000 MILES

A mechanic replaced a CV boot on the front axle of my BMW X5. Is there any possibility that they could have damaged the differential in the process of pulling off and replacing the axle? (I know that there was no differential leak the week prior to the replacement, and I know that immediately after the replacement, the differential began to leak from the gasket. They insist that it is pure coincidence, and that nothing they could have done would have ever damaged the differential.)

3 Replies

IMPALASS

MECHANIC
3,112 POSTS

Hello �

Yes things can be a coincidence... Things happen.

My experience on this is based off of assumptions since I can’t physically look to see. My thought if you look at the attached picture... Is that if they removed the axle that is labeled number 1 and replace both boots labeled number 2 then it is possible that the seal labeled number 6 was cut, torn or just plain worn which is what is causing the leak... Again... Without looking it is hard to say but this would seem reasonable.

In my experience, any time I remove an axle I always replace the seals. They have been in there in this case, 75,000 miles just like the boots were. I always replace both boots also.

Also, in some instances it is better cheaper sometimes to replace the entire axle....... But you would have to compare prices for that.

Anyway, it is possible that since the axle was removed and replace, if the leak is coming from where the axle inserts into the differential, then the seal is what is leaking.

Note, though they may have cut or torn it..... Again that seal was in there for 75,000 miles and moving the axle may have been just enough for it to get out of the shape it was in and now leak. Now is that their fault that the seal is old? No..... Should it have been replaced.....I would have.

So... Hope this helps

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Sunday, March 13th, 2011 AT 12:19 AM

TYRANOMIKE

MEMBER
2 POSTS

When I looked at the oily mess, I had no clue what I was examining. After I'd read a bit about differentials, I also had the theory that the seal had broken, but when I asked the the mechanic, he insisted that the leak was from around the gasket. Is it impossible to imagine that while pulling the old axle out or sticking the new axle in (they replaced my old one with a remanufactured axle; the remanufactured axle came completely assembled) they pried the two halves of the differential apart and caused the leak from the gasket? Thank you so much for your help.

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Sunday, March 13th, 2011 AT 9:44 PM

IMPALASS

MECHANIC
3,112 POSTS

Hello �

If I understand you correctly..... They didn’t completely remove the entire axle � they left part of it inside the differential?

Then they replaced the boot and put it all back together?

Did they replace one or both boots... Inner or outer

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Sunday, March 13th, 2011 AT 9:48 PM